mineral

Polished labradorite

Labradorite, calcium-rich plagioclase feldspar (approximately (Ca,Na)(Al,Si)₄O₈)

AI-generated identification · may be incorrect

Dark gray to black, polished surface with blue-green iridescent flashes (labradorescence); Mohs hardness 6–6.5, vitreous luster, triclinic crystal structure, and two good cleavage directions. The image’s small rounded shape suggests a tumbled or polished piece.

Identified August 20, 2026More mineral →

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Physical properties

Formation & geological history

Forms mainly in mafic igneous rocks such as gabbro, basalt, and anorthosite as magma cools; notable deposits are Precambrian in age, especially in Labrador, Canada. Similar material occurs in Madagascar, Finland, Russia, and elsewhere.

Uses & applications

Used for cabochons, beads, carvings, and decorative stone; larger slabs are used architecturally. Strong blue flash increases jewelry and collector appeal.

Geological facts

Its colors result from light interference between microscopic feldspar lamellae produced during cooling and solid-state exsolution.

Field identification & locations

Identify by gray body color, relatively soft feldspar hardness, cleavage, and angular blue flashes that change with viewing angle; avoid confusing it with moonstone or glass. Common sources include Canada and Madagascar.